1. Field of the Invention
The present invention relates to a single facer machine which is capable of selectively manufacturing single-faced corrugated boards having different kinds of flute.
2. Description of the Prior Art
As shown in FIG. 1, a single facer machine includes an upper roll 10, a lower roll 12 and a pressure roll 14 all supported by side frames (not shown) for rotation about a horizontal axis. The upper roll 10 and the lower roll 12 both have axially extending corrugations formed on the entire periphery thereof, and are supported by the side frames in such a manner as to mesh with each other at the respective corrugations. The pressure roll 14 is so constructed to be pressed against the lower roll 12 through a web of medium 16 and a linerboard 18. The medium 16 is fed into and passed between the upper roll 10 and the lower roll 12 where flutes are formed under pressure. The ridges or tips of the flutes are coated with glue by means of an adhesive applicator roll 22 of a glue mechanism 20. The linerboard 18, which is fed from a direction opposite to the medium 16, passes over the pressure roll 14 and into the nip between the upper and lower rolls 12 and 14, and is adhesively bonded to the flute tips of the medium 16 to thereby form a single-faced corrugated board 24.
It is to be noted that the single-faced corrugated boards 24 may be classified according to the height and the number of flutes per 30 cm formed on a web of medium 16: A-flute, B-flute, C-flute, D-flute,and E-flute. The kind of flute depends upon the corrugated configuration of the upper and lower rolls to be mounted on the machine.
As mentioned above, plural kinds of flute are available to form a single-faced corrugated board, and the kind of flute depends upon the corrugated configuration of the upper and lower rolls incorporated in the single facer machine. Thus, in order to form single-faced corrugated boards with different kinds of flute by one set of single facer machine, the upper and lower rolls of the machine have to be bodily replaced each time the kind of flute is changed. The roll replacement, however, requires complicated labor and considerable time. In addition, the combination of flute kinds of single-faced corrugated boards to be selectively produced is not random, and certain combinations are formed, for example; A-flute and E-flute, B-flute and E-flute, and C-flute and E-flute. Thus, the prior art has heretofore employed two sets of single facer machine juxtaposed in a single corrugator line, wherein the machines are selectively operated to produce two kinds of single-faced corrugated board within the range of certain combinations as described above.
Two general systems, the tandem system and the double-decker system, are known in the prior art for arranging two sets of single facer machine in a single corrugator line. The tandem system includes two sets of single facer machine arranged one behind the other or disposed in series in a corrugator line. The double-decker system includes two sets of single facer machine laid one on the other or arranged on two overlying decks. Either of the systems is selectively employed depending on the installation space available in each individual manufacturing plant.
Basically, in each of the two systems, the installation cost will inevitably be doubled because of the two sets of single facer machine arranged in a single corrugator line. In addition, the systems involve the following disadvantages in relation to installation area, efficiency of operation, and incidental equipment.
(1) In the tandem system, since two sets of single facer machine having entirely the same machine structure are arranged in series, additional installation area for at least one set of single facer machine is required and the space available in the plant may not be effectively utilized.
(2) In the double-decker system, apparently installation area for one set of machine will suffice, but the efficiency of operation of the upper machine will greatly be reduced because of two sets of single facer machine arranged one on the other.
(3) These systems require each two sets of power transmitting mechanisms such as speed reducers, of machine frames, and of pipings for steam and hydraulic/pneumatic systems. Also, the systems require each two sets of incidental equipment such as preheaters and take-up conveyors for transferring single-faced corrugated boards produced by the machines.
(4) The systems require each two sets of motors, and electric control systems such as control panels and consoles.
Japanese Laid-Open Patent Publication No. 54-143384 discloses an improved single facer machine which eliminates certain disadvantages associated with the prior art. As shown in FIG. 4 of the publication, the single facer machine includes dual pairs of upper and lower rolls journalled on a suspension member 30. The suspension member 30 is pivoted about a fixed shaft 31, thereby selectively bringing one pair of upper and lower rolls into contact with a pressure roll 34. However, the pair of upper and lower rolls are inherently very heavy and hence, in order to rotate the suspension member 30, which has the dual pairs of upper and lower rolls, for substantially 180 degrees to thereby alternately shift each pair of upper and lower rolls, extremely large-scaled drive mechanisms and support mechanisms are needed. Further, in order to stop the suspension member 30 in place, a high degree of positioning accuracy is required. All of these factors significantly add to the manufacturing cost.